MF, as in Mother F*****
Mj, ja
Castraphone is not a word!However...the answer is 4 pairs of letters...# ST (ST) # RaP (PqR) # HonE (EfgH) # ON (NO)
Two pairs of letters are there in the word ANSWER. 1) AnswE(AbcdE) - AE 2) NsweR(NopqR) - NR
Three pairs of letters are there. E and G, G and I & L and N are those three pairs.
Two, that I found.
There are two pairs of letters in the word preamble which have the same number of letters between them in the word as there are between the same letters in the English alphabet.(1) The A and the second E, with three letters between them:p.r.e.A.m.b.l.E........A.b.c.d.E...(2) The first E and the B, with two letters between them:p.r.E.a.m.B.l.e..a.B.c .d.E.....
Yellow
litter,flitter,cluttered,command,cheerleader
Mississippi has three sets of doubled letters, two double s pairs, and one double p pair. Tennessee also has three pairs of doubled letters in its name.
There are 12 letters in the following, with two pairs of doubles so the answer is 12!/[2!*2!] = 119,750,400
The letters form the word pairs "negative surgery" and "gate resurveying."
For the 4 letters, there are 12 discrete pairs of letters, but only 6 unique pairs. FI, FS, FH (and the mirrors IF, SF, HF) IS, IH (and the mirrors SI and HI) SH (and the mirror HS)